…index lookups, if the columns that are being fetched do not belong to the secondary index definition (and hence covering index…. Thereby, converting Random access to one or more sequential access. There is one …, because we want to see the individual affect of an optimization (where possible). …
Post: Multi Column indexes vs Index Merge
September 19, 2009 By 30 Comments
… how indexes are created. Quite commonly people just index individual columns as they are referenced in where clause thinking this is the optimal indexing… covering index) MySQL gets a “row pointer” which can be primary key value (for Innodb tables) physical file offset (for MyISAM tables) or…
Comment: Countless storage engines
May 4, 2007 By 6 Comments
…covering indexes is not critical because it does not require a lot of random IO. But in the same case the fact indexes…cache full pages not individual rows does not bother you too much. Also optimized index retrieval does not…ie 20GB in Innodb and 14GB in falcon or 30GB in Innodb and 21GB in Falcon we…
Post: How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
…is far more extensive than this article can cover, and might wander into Apache, networking config, caching… or something like that.) In the common case, though, a query simply needs a rewrite or a new index or …to pull out the statements and analyze them individually. The goal is always to develop X-…
Comment: MySQL Full Text Search in Action
January 12, 2010 By 9 Comments
… to search against each individually, or against main paired with one or the other complement, should i also have individual indexes, or only multi column? 1) fulltext(main),fulltext(first),fulltext(alternative),fulltext(main,first),fulltext(main,alternative) or 2) —————fulltext… will be covered by either one of last two, but will it be faster for search to have also index on only…
Post: Missing Data - rows used to generate result set
July 20, 2008 By 15 Comments
… of queries. If you’re joining multiple tables or if you have GROUP BY query the number…indexes. If you have WHERE ID%100=0 you can have extra column divisible_by_hundred and keep it indexed… as individual row which just was accessed. At the same time I think starting with something and covering basic…
Post: XtraDB: The Top 10 enhancements
August 13, 2009 By 5 Comments
… lot of it depends on the individual workload. My ranking method was…from the InnoDB plugin, which has fast index creation (as opposed to recreating the …(a full buffer provides no use) or reduce its size (see docs). Data …All of these 10 items will be covered in our Training workshops for InnoDB …
